Odd/Even Identities
Plus/Minus Identities
Trig identities which show whether
each trig function is an odd
function or an even function.
Odd/Even Identities

sin (–x) = –sin x
cos (–x) = cos x
tan (–x) = –tan x  csc (–x) = –csc x
sec (–x) = sec x
cot (–x) = –cot x 
